[turbofan] Support lowering of ChangeFloat64ToTagged/ChangeTaggedToInt32.

src/compiler/common-operator.h

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_COMPILER_COMMON_OPERATOR_H_
 #define V8_COMPILER_COMMON_OPERATOR_H_
 
 #include "src/v8.h"
 
 #include "src/assembler.h"
@@ skipping 116 matching lines @@
   }
   Operator* EffectPhi(int arguments) {
     DCHECK(arguments > 0);  // Disallow empty phis.
     return new (zone_) Operator1<int>(IrOpcode::kEffectPhi, Operator::kPure, 0,
                                       0, "EffectPhi", arguments);
   }
   Operator* ControlEffect() {
     return new (zone_) SimpleOperator(IrOpcode::kControlEffect, Operator::kPure,
                                       0, 0, "ControlEffect");
   }
+  Operator* ValueEffect(int arguments) {
+    DCHECK(arguments > 0);  // Disallow empty value effects.
+    return new (zone_) SimpleOperator(IrOpcode::kValueEffect, Operator::kPure,
+                                      arguments, 0, "ValueEffect");
+  }
   Operator* Finish(int arguments) {
     DCHECK(arguments > 0);  // Disallow empty finishes.
     return new (zone_) Operator1<int>(IrOpcode::kFinish, Operator::kPure, 1, 1,
                                       "Finish", arguments);
   }
   Operator* StateValues(int arguments) {
     return new (zone_) Operator1<int>(IrOpcode::kStateValues, Operator::kPure,
                                       arguments, 1, "StateValues", arguments);
   }
   Operator* FrameState(BailoutId ast_id) {
@@ skipping 137 matching lines @@
 
 template <typename T>
 inline T ValueOf(Operator* op) {
   return CommonOperatorTraits<T>::ValueOf(op);
 }
 }
 }
 }  // namespace v8::internal::compiler
 
 #endif  // V8_COMPILER_COMMON_OPERATOR_H_